1. Field of the Invention
This invention relates to the recovery of gold from gold-bearing liquors, particularly such liquors obtainable in the known cyanidation process.
2. Description of the Prior Art
The cyanidation process is a well known process for extracting gold values from gold bearing ores. The process involves finely grinding the ore and then leaching the ore with a suitable cyanide solution. The cyanide leach solution is generally a sodium cyanide leach solution which contains calcium hydroxide or other suitable alkali to maintain the pH above about 10. The gold values are leached in the form of the aurocyanide (Au(CN).sub.2) ions. The following reaction occurs with sodium cyanide leach solution: EQU 2Au+4NaCN+O.sub.2 +H.sub.2 O.fwdarw.2Na Au(CN).sub.2 +2Na OH.
the gold values may be recovered from the gold rich leach solution by any of a number of methods. The preferred method is to adsorb the gold values onto activated carbon and then desorb the gold values therefrom by treating the loaded carbon with water of low ionic strength such as softened or deionised water. Such methods are described in the specification of our South African Pat. No. 73/8939 and the specification of our co-pending South African patent application No. 76/4204.